Magnetic field adjusting three-dimensional flexible resonator for wireless power transmission system

ABSTRACT

A stereoscopic flexible resonator is provided. The stereoscopic flexible stereoscopic resonator includes at least one cell, at least one resonator including a capacitor, and a connection unit configured to connect the cell and the resonator in a stereoscopic structure.

PRIORITY

This application is a National Phase Entry of PCT InternationalApplication No. PCT/KR2013/009403, which was filed on Oct. 22, 2013, andclaims priority to Korean Patent Application No. 10-2012-0117646, whichwas filed on Oct. 23, 2012 in the Korean Intellectual Property Office,the contents of which are incorporated herein by reference.

BACKGROUND

1. Field of the Invention

The present invention relates generally to a wireless power transmissionsystem, and more particularly, to a stereoscopic flexible stereoscopicresonator.

2. Description of the Related Art

Wireless power refers to energy that is transmitted from a wirelesspower transmission apparatus to a wireless power reception apparatus viamagnetic coupling. Accordingly, a wireless power charging systemincludes a source device configured to wirelessly transmit power, and atarget device configured to wirelessly receive power. The source devicemay be referred to as a wireless power transmission apparatus, and thetarget device may be referred to as a wireless power receptionapparatus.

The source device may include a source resonator, and the target devicemay include a target resonator. Magnetic coupling or resonant couplingmay be formed between the source resonator and the target resonator.

SUMMARY

The present invention has been made to address the above-mentionedproblems and disadvantages, and to provide at least the advantagesdescribed below. Accordingly, an aspect of the present inventionprovides a stereoscopic flexible resonator that includes at least onecell, at least one resonator including a capacitor, and a connectionunit to connect the cell and the resonator in a stereoscopic structure.

In accordance with an aspect of the present invention, a stereoscopicflexible resonator is provided. The stereoscopic flexible stereoscopicresonator includes at least one cell, at least one resonator including acapacitor, and a connection unit configured to connect the cell and theresonator in a stereoscopic structure.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other aspects, features, and advantages of the presentinvention will be more apparent from the following description, taken inconjunction with the accompanying drawings, in which:

FIG. 1 illustrates a wireless power transmission system according to anembodiment of the present invention;

FIGS. 2A and 2B illustrate a distribution of a magnetic field in afeeder and a resonator according to an embodiment of the presentinvention;

FIGS. 3A and 3B illustrate a resonator and a feeder according to anembodiment of the present invention;

FIGS. 4A and 4B illustrate a distribution of a magnetic field within aresonator based on feeding of a feeder according to an embodiment of thepresent invention;

FIG. 5 illustrates an electric vehicle charging system according to anembodiment of the present invention;

FIGS. 6A to 7B illustrate applications using a wireless power receptionapparatus and a wireless power transmission apparatus according to anembodiment of the present invention;

FIG. 8 illustrate a wireless power transmission apparatus and a wirelesspower reception apparatus according to an embodiment of the presentinvention;

FIGS. 9A and 9B illustrate a stereoscopic flexible resonator, and afield distribution based on a resonance mode of a resonator according toan embodiment of the present invention:

FIGS. 10A and 10B illustrate examples of a structure of a stereoscopicflexible resonator according to an embodiment of the present invention;

FIGS. 11A to 11C illustrate examples of a connection unit of astereoscopic flexible resonator according to an embodiment of thepresent invention; and

FIGS. 12A and 12B illustrate examples of a resonance mode based on aselection of a connection unit of a stereoscopic flexible resonatoraccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

Recently, various portable electronic products have been released, alongwith the development of Information Technologies (IT). Such anenvironment has led to a surge in a quantity of terminals that arepossessed and carried by each individual. Accordingly, as portableelectronic products are diversified and made more complex, powercharging of devices has emerged as an issue. In home appliances, as wellas portable devices, data may be transmitted wirelessly, however, powerlines are required at all times due to power.

A wireless power transmission technology enabling a power supply withoutusing a power line has been increasingly highlighted. For example, whenwireless power transmission technology is commercialized, energy may beeasily supplied to a wired charging system that is currently used.Wireless power transmission may enable power charging at any time andanywhere, and may realize an environment enabling the sharing of a powersource between devices even without a power source. Additionally, thewireless power transmission may prevent the pollution of nature and theenvironment by used batteries.

When wireless power transmission is applied to Consumer Electronics (CE)devices (for example, mobile phones, cameras, and the like), mobiledevices, and medical devices (for example, hearing aids, medicalsensors, and the like), a first priority may be to enhance powertransmission efficiency. Typically, power transmission efficiency mayquickly change due to a change in a location or an angle of a device.Accordingly, a user may need to be informed of a sudden change in powertransmission efficiency, and may experience inconvenience of having toplace the device in a predetermined location.

Therefore, a resonator that may transmit optimum power and maintainpower transmission efficiency, despite a change in location or angle ofa wireless charging device based on user convenience and an enhancementin power transmission efficiency is required. The above technology isalso applicable to wireless charging and a transmission system used inmedical devices as well as CE devices.

In a resonator according to an embodiment of the present invention,power transmission efficiency is maintained, and optimum power istransmitted to a mobile device, a medical device, and the like in awireless charging and transmission system, despite a change in alocation or an angle of a device based on user convenience.

Hereinafter, embodiments of the present invention are further describedbelow with reference to the accompanying drawings.

A scheme of communicating between a source and a target may include anin-band communication scheme and an out-of-band communication scheme. Inthe in-band communication scheme, the source and the target communicatewith each other using the same frequency band that is used for powertransmission. In the out-of-band communication scheme, the source andthe target communicate with each other using a frequency band that isdifferent from a frequency band that is used for power transmission.

FIG. 1 illustrates an example of a wireless power transmission systemaccording to an embodiment of the present invention.

Referring to FIG. 1, the wireless power transmission system includes asource 110 and a target 120. The source 110 refers to a deviceconfigured to supply wireless power, and includes all electronic devicescapable of supplying power, for example a pad, a terminal, a television(TV), and the like. The target 120 refers to a device configured toreceive supplied wireless power, and includes all electronic devicesrequiring power, for example a terminal, a TV, a vehicle, a washingmachine, a radio, an electric light, and the like.

The source 110 includes a variable Switching Mode Power Supply (SMPS)111, a Power Amplifier (PA) 112, a matching network 113, a transmission(TX) controller 114 (for example, a TX control logic), a communicationunit 115, and a power detector 116.

The variable SMPS 111 generates Direct Current (DC) voltage by switchingAlternating Current (AC) voltage in a band of tens of Hertz (Hz) outputfrom a power supply. The variable SMPS 111 outputs DC voltage of apredetermined level, or may adjust an output level of DC voltage basedon the control of the TX controller 114.

The power detector 116 detects output current and output voltage of thevariable SMPS 111, and transfers, to the TX controller 114, informationon the detected current and the detected voltage. Additionally, thepower detector 116 detects input current and input voltage of the PA112.

The PA 112 generates power by converting DC voltage of a predeterminedlevel to AC voltage, using a switching pulse signal in a band of a fewmegahertz (MHz) to tens of MHz. Accordingly, the PA 112 converts DCvoltage supplied to the PA 112 to AC voltage, using a reference resonantfrequency F_(Ref), and generates communication power used forcommunication, or charging power used for charging. The communicationpower and the charging power may be used in a plurality of targetdevices.

The communication power refers to low power of 0.1 milliwatt (mW) to 1mW. The charging power refers to high power of 1 mW to 200 W that isconsumed in a device load of a target device. In an embodiment of thepresent invention described herein, the term “charging” may be used torefer to supplying power to a unit or element that is configured tocharge power. Additionally, the term “charging” may be used to refer tosupplying power to a unit or element that is configured to consumepower. The units or elements may include, for example, batteries,displays, sound output circuits, main processors, and various sensors.

Also, the term “reference resonant frequency” refers to a resonantfrequency that is used by the source 110. Additionally, the term“tracking frequency” refers to a resonant frequency that is adjusted bya preset scheme.

The TX controller 114 detects a reflected wave of the communicationpower or the charging power, and detects mismatching that occurs betweena target resonator 133 and a source resonator 131 based on the detectedreflected wave. To detect mismatching, for example, the TX controller114 detects an envelope of the reflected wave, a power amount of thereflected wave, and the like.

The matching network 113 compensates for impedance mismatching betweenthe source resonator 131 and the target resonator 133 to achieve optimalmatching, under the control of the TX controller 114. The matchingnetwork 113 is connected through a switch, based on a combination of acapacitor and an inductor, under the control of the TX controller 114.

The TX controller 114 calculates a Voltage Standing Wave Ratio (VSWR),based on a voltage level of the reflected wave, and based on a level ofan output voltage of the source resonator 131 or the PA 112. Forexample, when the VSWR is greater than a predetermined value, the TXcontroller 114 determines that mismatching is detected.

In another example, when the VSWR is less than the predetermined value,the TX controller 114 calculates a power transmission efficiency foreach of N tracking frequencies, determines a tracking frequency F_(Best)with the best power transmission efficiency among the N trackingfrequencies, and adjusts the reference resonant frequency F_(Ref) to thetracking frequency F_(Best). In various examples, the N trackingfrequencies may be set in advance.

The TX controller 114 adjusts a frequency of a switching pulse signal.Under the control of the TX controller 114, the frequency of theswitching pulse signal is determined. For example, by controlling the PA112, the TX controller 114 generates a modulation signal to betransmitted to the target 120. In other words, the communication unit115 transmits a variety of data 140 to the target 120 using in-bandcommunication. The TX controller 114 detects a reflected wave, anddemodulates a signal received from the target 120 through an envelope ofthe detected reflected wave.

The TX controller 114 generates a modulation signal for in-bandcommunication, using various methods. For example, the TX controller 114generates the modulation signal by turning on or off a switching pulsesignal, by performing delta-sigma modulation, and the like.Additionally, the TX controller 114 generates a Pulse-Width Modulation(PWM) signal with a predetermined envelope.

The communication unit 115 performs out-of-band communication thatemploys a communication channel. The communication unit 115 includes acommunication module, such as one configured to process ZigBee,Bluetooth, and the like. The communication unit 115 transmits the data140 to the target 120 through the out-of-band communication.

The source resonator 131 transfers an electromagnetic energy 130 to thetarget resonator 133. For example, the source resonator 131 transfersthe communication power or charging power to the target 120, usingmagnetic coupling with the target resonator 133.

The target 120 includes a matching network 121, a rectifier 122, aDC-to-DC (DC/DC) converter 123, a communication unit 124, a reception(RX) controller 125 (for example, an RX control logic), and a powerdetector 127.

The target resonator 133 receives the electromagnetic energy 130 fromthe source resonator 131. For example, the target resonator 133 receivesthe communication power or charging power from the source 110, using themagnetic coupling with the source resonator 131. Additionally, thetarget resonator 133 receives the data 140 from the source 110 usingin-band communication.

The matching network 121 matches an input impedance viewed from thesource 110 to an output impedance viewed from a load. The matchingnetwork 121 is configured with a combination of a capacitor and aninductor.

The rectifier 122 generates DC voltage by rectifying an AC voltage. Forexample, the rectifier 122 rectifies AC voltage received from the targetresonator 133.

The DC/DC converter 123 adjusts a level of the DC voltage that is outputfrom the rectifier 122, based on a capacity required by the load. Forexample, the DC/DC converter 123 adjusts the level of the DC voltageoutput from the rectifier 122 from 3 volts (V) to 10 V.

The power detector 127 detects voltage at an input 126 of the DC/DCconverter 123, and detects current and voltage at an output of the DC/DCconverter 123. The detected voltage at the input 126 is used tocalculate a transmission efficiency of power received from the source110. Additionally, the detected current and the detected voltage at theoutput is used by the RX controller 125 to calculate an amount of powertransferred to the load. The TX controller 114 of the source 110determines an amount of power that must be transmitted by the source110, based on power required by the load and power transferred to theload.

When power of the output calculated using the communication unit 124 istransferred to the source 110 comprising the RX controller 125, thesource 110 calculates an amount of power that must be transmitted.

The communication unit 124 performs in-band communication fortransmitting or receiving data using a resonance frequency. Duringin-band communication, the RX controller 125 demodulates a receivedsignal by detecting a signal between the target resonator 133 and therectifier 122, or detecting an output signal of the rectifier 122. Forexample, the RX controller 125 demodulates a message received usingin-band communication. Additionally, the RX controller 125 adjusts animpedance of the target resonator 133 using the matching network 121 tomodulate a signal transmitted to the source 110. For example, the RXcontroller 125 increases the impedance of the target resonator 133, sothat a reflected wave may be detected from the TX controller 114 of thesource 110. Depending on whether the reflected wave is detected, the TXcontroller 114 may detect a binary number, for example a “0” or a “1.”

The communication unit 124 transmits a response message to thecommunication unit 115 of the source 110. For example, the responsemessage may include at least one of a type of a corresponding target,information about a manufacturer of a corresponding target, a model nameof a corresponding target, a battery type of a corresponding target, ascheme of charging a corresponding target, an impedance value of a loadof a corresponding target, information on characteristics of a targetresonator of a corresponding target, information on a frequency bandused by a corresponding target, an amount of a power consumed by acorresponding target, an IDentifier (ID) of a corresponding target, andinformation on version or standard of a corresponding target. A type ofinformation included in the response message may be changed based onimplementation.

The communication unit 124 performs out-of-band communication using acommunication channel. For example, the communication unit 124 includesa communication module, such as one configured to process ZigBee,Bluetooth, and the like. The communication unit 124 transmits orreceives the data 140 to or from the source 110 using out-of-bandcommunication.

The communication unit 124 receives a wake-up request message from thesource 110, and the power detector 127 detects an amount of powerreceived by the target resonator 133. The communication unit 124transmits, to the source 110, information on the detected amount ofpower. Information on the detected amount of power includes, forexample, an input voltage value and an input current value of therectifier 122, an output voltage value and an output current value ofthe rectifier 122, an output voltage value and an output current valueof the DC/DC converter 123, and the like.

In FIG. 1, the TX controller 114 sets a resonance bandwidth of thesource resonator 131. Based on a setting of the resonance bandwidth ofthe source resonator 131, a Quality factor or Q-factor of the sourceresonator 131 is determined.

Additionally, the RX controller 125 sets a resonance bandwidth of thetarget resonator 133. Based on a setting of the resonance bandwidth ofthe target resonator 133, a Q-factor of the target resonator 133 isdetermined. For example, the resonance bandwidth of the source resonator131 may be set to be greater than or less than the resonance bandwidthof the target resonator 133.

The source 110 and the target 120 communicate with each other in orderto share information about the resonance bandwidth of the sourceresonator 131 and the resonance bandwidth of the target resonator 133.In an example in which power desired or required by the target device120 is greater than a reference value, the Q-factor of the sourceresonator 131 is set to a value greater than “100.” In another examplein which the power desired or required by the target 120 is less thanthe reference value, the Q-factor of the source resonator 131 is set toa value less than “100.”

In wireless power transmission employing a resonance scheme, resonancebandwidth is an important factor. A Q-factor considers a change in adistance between the source resonator 131 and the target resonator 133,a change in the resonance impedance, impedance mismatching, a reflectedsignal, and the like, and is represented by Qt. In this example, Qt hasan inverse-proportional relationship with resonance bandwidth, asindicated in Equation (1) below.

$\begin{matrix}\begin{matrix}{\frac{\Delta\; f}{f_{0}} = \frac{1}{Qt}} \\{= {\Gamma_{S,D} + \frac{1}{{BW}_{S}} + \frac{1}{{BW}_{D}}}}\end{matrix} & (1)\end{matrix}$

In Equation (1) above, f₀ denotes a central frequency, Δf denotes achange in a bandwidth, Γ_(S,D) denotes a reflection loss between thesource resonator 131 and the target resonator 133, BW_(S) denotes theresonance bandwidth of the source resonator 131, and BW_(D) denotes theresonance bandwidth of the target resonator 133.

An efficiency U of the wireless power transmission is defined asindicated in Equation (2) below.

$\begin{matrix}{U = {\frac{\kappa}{\sqrt{\Gamma_{S}\Gamma_{D}}} = {\frac{\omega_{0}M}{\sqrt{R_{S}R_{D}}} = \frac{\sqrt{Q_{S}Q_{D}}}{Q_{\kappa}}}}} & (2)\end{matrix}$

In Equation (2) above, κ denotes a coupling coefficient of energycoupling between the source resonator 131 and the target resonator 133,Γ_(S) denotes a reflection coefficient in the source resonator 131,Γ_(D) denotes a reflection coefficient in the target resonator 133, ω₀denotes a resonant frequency, M denotes a mutual inductance between thesource resonator 131 and the target resonator 133, R_(S) denotes animpedance of the source resonator 131, R_(D) denotes an impedance of thetarget resonator 133, Q_(S) denotes a Q-factor of the source resonator131, Q_(D) denotes a Q-factor of the target resonator 133, and Q_(κ)denotes a Q-factor of the energy coupling between the source resonator131 and the target resonator 133.

Referring to Equation (2) above, the Q-factors has high relevance to theefficiency of the wireless power transmission.

Accordingly, to increase the efficiency of wireless power transmission,the Q-factors are set to high values. For example, when the Q-factorsQ_(S) and Q_(D) are set to extremely high values, the efficiency of thewireless power transmission is reduced due to a change in the couplingcoefficient c, a change in the distance between the source resonator 131and the target resonator 133, a change in the resonance impedance,impedance mismatching, and the like.

Additionally, to increase the efficiency of wireless power transmission,when the resonance bandwidth of the source resonator 131, and theresonance bandwidth of the target resonator 133 are set to beexcessively narrow, impedance mismatching and the like occurs due toeven a small external effect. Considering impedance mismatching,Equation 1 is represented as indicated in Equation (3) below.

$\begin{matrix}{\frac{\Delta\; f}{f_{0}} = \frac{\sqrt{VSWR} - 1}{{Qt}\sqrt{VSWR}}} & (3)\end{matrix}$

In FIG. 1, the source 110 wirelessly transmits wake-up power used towake up the target 120, and broadcasts a configuration signal used toconfigure a wireless power transmission network. The source 110receives, from the target 120, a search frame including a value ofreceiving sensitivity of the configuration signal, permits interactionwith the target 120, and transmits, to the target 120, an ID used toidentify the target 120 in the wireless power transmission network.Additionally, the source 110 generates charging power through powercontrol, and wirelessly transmits the charging power to the target 120.

Additionally, the target 120 receives wake-up power from at least one ofa plurality of source devices, and activates a communication functionusing the wake-up power. The target 120 receives a configuration signalused to configure a wireless power transmission network of each of theplurality of source devices, selects the source 110 based on receivingsensitivity of the configuration signal, and wirelessly receives powerfrom the selected source 110.

In the following description, the term “resonator” used to describeFIGS. 2 through 4 refers to both a source resonator and a targetresonator.

FIGS. 2A and 2B illustrate examples of a distribution of a magneticfield in a feeder and a resonator according to an embodiment of thepresent invention.

When a resonator receives power supplied through a separate feeder,magnetic fields are formed in both the feeder and the resonator.

Referring to FIG. 2A, as input current flows into a feeder 210, amagnetic field 230 is formed. A direction 231 of the magnetic field 230within the feeder 210 has a phase that is opposite to a phase of adirection 233 of the magnetic field 230 outside the feeder 210. Themagnetic field 230 formed by the feeder 210 causes induced current to beformed in a resonator 220. The direction of the induced current isopposite to a direction of the input current.

Due to the induced current, a magnetic field 240 is formed in theresonator 220. Directions of a magnetic field formed due to inducedcurrent in all positions of the resonator 220 may be the same.Accordingly, a direction 241 of the magnetic field 240 formed by theresonator 220 may have the same phase as a direction 243 of the magneticfield 240 formed by the resonator 220.

Consequently, when the magnetic field 230 formed by the feeder 210 andthe magnetic field 240 formed by the resonator 220 are combined,strength of the total magnetic field may decrease within the feeder 210,however, the strength may increase outside the feeder 210. In an examplein which power is supplied to the resonator 220 through the feeder 210configured as illustrated in FIG. 2A, the strength of the total magneticfield may decrease in the center of the resonator 220, but may increaseoutside the resonator 220. In another example in which a magnetic fieldis randomly distributed in the resonator 220, it may be difficult toperform impedance matching, since an input impedance may frequentlyvary. Additionally, when the strength of the total magnetic field isincreased, an efficiency of wireless power transmission may beincreased. Conversely, when the strength of the total magnetic field isdecreased, the efficiency for wireless power transmission may bereduced. Accordingly, the power transmission efficiency may be reducedon average.

FIG. 2B illustrates an example of a structure of a wireless powertransmission apparatus in which a source resonator 250 and a feeder 260have a common ground. The source resonator 250 includes a capacitor 251.The feeder 260 receives an input of a Radio Frequency (RF) signal via aport 261. For example, when the RF signal is input to the feeder 260,input current is generated in the feeder 260. The input current flowingin the feeder 260 causes a magnetic field to be formed, and a current isinduced in the source resonator 250 by the magnetic field. Additionally,another magnetic field is formed due to the induced current flowing inthe source resonator 250. In this example, a direction of the inputcurrent flowing in the feeder 260 has a phase opposite to a phase of adirection of the induced current flowing in the source resonator 250.Accordingly, in a region between the source resonator 250 and the feeder260, a direction 271 of the magnetic field formed due to the inputcurrent has the same phase as a direction 273 of the magnetic fieldformed due to the induced current, and thus the strength of the totalmagnetic field increases. Conversely, within the feeder 260, a direction281 of the magnetic field formed due to the input current may have aphase opposite to a phase of a direction 283 of the magnetic fieldformed due to the induced current, and thus the strength of the totalmagnetic field decreases. Therefore, the strength of the total magneticfield decreases in the center of the source resonator 250 but increasesoutside the source resonator 250.

The feeder 260 determines an input impedance by adjusting an internalarea of the feeder 260. The input impedance refers to an impedanceviewed in a direction from the feeder 260 to the source resonator 250.When the internal area of the feeder 260 is increased, the inputimpedance is increased. Conversely, when the internal area of the feeder260 is reduced, the input impedance is reduced. Because the magneticfield is randomly distributed in the source resonator 250 despite areduction in the input impedance, a value of the input impedance variesbased on a location of a target device. Accordingly, a separate matchingnetwork is required to match the input impedance to an output impedanceof a PA. For example, when the input impedance is increased, a separatematching network is used to match the increased input impedance to arelatively low output impedance.

In an example in which a target resonator has the same configuration asthe source resonator 250, and when a feeder of the target resonator hasthe same configuration as the feeder 260, a separate matching network isrequired, because a direction of current flowing in the target resonatorhas a phase opposite to a phase of a direction of induced currentflowing in the feeder of the target resonator.

FIGS. 3A and 3B illustrate a resonator and a feeder according to anembodiment of the present invention.

Referring to FIG. 3A, the wireless power transmission apparatus includesa resonator 310, and a feeder 320. The resonator 310 includes acapacitor 311. The feeder 320 is electrically connected to both ends ofthe capacitor 311.

FIG. 3B illustrates, in more detail, a structure of the wireless powertransmission apparatus of FIG. 3A. The resonator 310 in FIG. 3A includesa first transmission line, a first conductor 341, a second conductor342, and at least one first capacitor 350.

The first capacitor 350 is inserted in series between a first signalconducting portion 331 and a second signal conducting portion 332 in thefirst transmission line, and an electric field is confined within thefirst capacitor 350. For example, the first transmission line includesat least one conductor in an upper portion of the first transmissionline and at least one conductor in a lower portion of the firsttransmission line. Current flows through the at least one conductordisposed in the upper portion of the first transmission line. The atleast one conductor disposed in the lower portion of the firsttransmission line may be electrically grounded. For example, a conductordisposed in an upper portion of the first transmission line may beseparated into and referred to as the first signal conducting portion331 and the second signal conducting portion 332. A conductor disposedin a lower portion of the first transmission line may be referred to asa first ground conducting portion 333.

As illustrated in FIG. 3B, the resonator 310 has a generallytwo-dimensional (2D) structure. The first transmission line includes thefirst signal conducting portion 331 and the second signal conductingportion 332 in the upper portion of the first transmission line. Inaddition, the first transmission line includes the first groundconducting portion 333 in the lower portion of the first transmissionline. The first signal conducting portion 331 and the second signalconducting portion 332 face the first ground conducting portion 333.Current flows through the first signal conducting portion 331 and thesecond signal conducting portion 332.

Additionally, one end of the first signal conducting portion 331 iselectrically connected (i.e., shorted) to the first conductor 341, andanother end of the first signal conducting portion 331 is connected tothe first capacitor 350, as illustrated in FIG. 3B. One end of thesecond signal conducting portion 332 is shorted to the second conductor342, and another end of the second signal conducting portion 332 isconnected to the first capacitor 350. Accordingly, the first signalconducting portion 331, the second signal conducting portion 332, thefirst ground conducting portion 333, and the conductors 341 and 342 areconnected to each other, so that the resonator 310 has an electricallyclosed-loop structure. The term “loop structure” includes, for example,a polygonal structure such as a circular structure, a rectangularstructure, and the like. “Having a loop structure” is a phrase thatindicates that a circuit is electrically closed.

The first capacitor 350 is inserted into an intermediate portion of thefirst transmission line. For example, the first capacitor 350 isinserted into a space between the first signal conducting portion 331and the second signal conducting portion 332. The first capacitor 350may be configured as a lumped element, a distributed element, and thelike. For example, a capacitor configured as a distributed element mayinclude zigzagged conductor lines and a dielectric material that has ahigh permittivity positioned between the zigzagged conductor lines.

When the first capacitor 350 is inserted into the first transmissionline, the resonator 310 has a characteristic of a metamaterial.“Metamaterial” indicates a material having a predetermined electricalproperty that has not been discovered in nature, and thus, may have anartificially designed structure. An electromagnetic characteristic of amaterial existing in nature may have a unique magnetic permeability or aunique permittivity. Most materials have a positive magneticpermeability or a positive permittivity.

In the case of most materials, a right hand rule may be applied to anelectric field, a magnetic field, and a pointing vector, and thus, thecorresponding materials may be referred to as Right Handed Materials(RHMs). However, a metamaterial that has a magnetic permeability or apermittivity absent in nature may be classified as an Epsilon NeGative(ENG) material, a Mu NeGative (MNG) material, a Double NeGative (DNG)material, a Negative Refractive Index (NRI) material, a Left-Handed (LH)material, and the like, based on a sign of the correspondingpermittivity or magnetic permeability.

When a capacitance of the first capacitor 350 inserted as the lumpedelement is appropriately determined, the resonator 310 has thecharacteristic of a metamaterial. Because the resonator 310 may have anegative magnetic permeability by appropriately adjusting thecapacitance of the first capacitor 350, the resonator 310 may also bereferred to as an MNG resonator. Various criteria may be applied todetermine the capacitance of the first capacitor 350. For example, thevarious criteria may include a criterion for enabling the resonator 310to have the characteristic of a metamaterial, a negative magneticpermeability in a target frequency, a zero-th order resonancecharacteristic in the target frequency, and the like. Based on at leastone criterion among the aforementioned criteria, the capacitance of thefirst capacitor 350 is determined.

The resonator 310, also referred to as an MNG resonator 310, may have azero-th order resonance characteristic of having, as a resonancefrequency, a frequency when a propagation constant is “0.” Because theresonator 310 may have a zero-th order resonance characteristic, theresonance frequency may be independent with respect to a physical sizeof the MNG resonator 310. By appropriately designing or configuring thefirst capacitor 350, the MNG resonator 310 may sufficiently change theresonance frequency without changing the physical size of the MNGresonator 310.

In a near field, for instance, the electric field may be concentrated onthe first capacitor 350 inserted into the first transmission line.Accordingly, due to the first capacitor 350, the magnetic field maybecome dominant in the near field. The MNG resonator 310 may have arelatively high Quality argument or Q-argument using the first capacitor350 of the lumped element, and thus, it may be possible to enhance theefficiency of power transmission. For example, the Q-argument indicatesa level of ohmic loss or a ratio of a reactance with respect to aresistance in wireless power transmission. The efficiency of wirelesspower transmission increases according to an increase in the Q-argument.

A magnetic core may be further provided to pass through the MNGresonator 310. The magnetic core performs a function of increasing apower transmission distance.

Referring to FIG. 3B, the feeder 320 in FIG. 3A includes a secondtransmission line, a third conductor 371, a fourth conductor 372, afifth conductor 381, and a sixth conductor 382.

The second transmission line includes a third signal conducting portion361 and a fourth signal conducting portion 362 in an upper portion ofthe second transmission line. In addition, the second transmission lineincludes a second ground conducting portion 363 in a lower portion ofthe second transmission line. The third signal conducting portion 361and the fourth signal conducting portion 362 face the second groundconducting portion 363. Current flows through the third signalconducting portion 361 and the fourth signal conducting portion 362.

Additionally, one end of the third signal conducting portion 361 isshorted to the third conductor 371, and the other end of the thirdsignal conducting portion 361 is connected to the fifth conductor 381,as illustrated in FIG. 3B. One end of the fourth signal conductingportion 362 is shorted to the fourth conductor 372, and the other end ofthe fourth signal conducting portion 362 is connected to the sixthconductor 382. The fifth conductor 381 is connected to the first signalconducting portion 331, and the sixth conductor 382 is connected to thesecond signal conducting portion 332. The fifth conductor 381 and thesixth conductor 382 are connected in parallel to both ends of the firstcapacitor 350. In this example, the fifth conductor 381 and the sixthconductor 382 are used as input ports to receive an RF signal as aninput.

Accordingly, the third signal conducting portion 361, the fourth signalconducting portion 362, the second ground conducting portion 363, thethird conductor 371, the fourth conductor 372, the fifth conductor 381,the sixth conductor 382, and the resonator 310 are connected to eachother, so that the resonator 310 and the feeder 320 may have anelectrically closed-loop structure. The term “loop structure” includes,for example, a polygonal structure such as a circular structure, arectangular structure, and the like. When an RF signal is received viathe fifth conductor 381 or the sixth conductor 382, input current flowsin the feeder 320 and the resonator 310, a magnetic field is formed dueto the input current, and a current is induced in the resonator 310 bythe formed magnetic field. A direction of the input current flowing inthe feeder 320 is the same as a direction of the induced current flowingin the resonator 310 and thus, the strength of the total magnetic fieldincreases in the center of the resonator 310, but decreases outside ofthe resonator 310.

An input impedance is determined based on an area of a region betweenthe resonator 310 and the feeder 320 and accordingly, a separatematching network used to match the input impedance to an outputimpedance of a PA may not be required. For example, even when thematching network is used, the input impedance may be determined byadjusting a size of the feeder 320 and thus, a structure of the matchingnetwork may be simplified. The simplified structure of the matchingnetwork may minimize a matching loss of the matching network.

The second transmission line, the third conductor 371, the fourthconductor 372, the fifth conductor 381, and the sixth conductor 382 formthe same structure as the resonator 310. In an example in which theresonator 310 has a loop structure, the feeder 320 may also have a loopstructure. In another example in which the resonator 310 has a circularstructure, the feeder 320 may also have a circular structure.

FIGS. 4A and 4B illustrate a distribution of a magnetic field within aresonator based on feeding of a feeder according to an embodiment of thepresent invention.

A feeding operation refers to supplying power to a source resonator inwireless power transmission, or refers to supplying AC power to arectifier in wireless power transmission. FIG. 4A illustrates adirection of input current flowing in the feeder, and a direction ofinduced current induced in the source resonator. Additionally, FIG. 4Aillustrates a direction of a magnetic field formed due to the inputcurrent of the feeder, and a direction of a magnetic field formed due tothe induced current of the source resonator.

Referring to FIG. 4A, the fifth conductor 381 or the sixth conductor 382of the feeder 320 may be used as an input port 410. The input port 410receives an RF signal as an input. The RF signal is output from a PA.The PA increases or decreases an amplitude of the RF signal based on ademand by a target device. The RF signal received by the input port 410is displayed in the form of input current flowing in the feeder. Theinput current flows in a clockwise direction in the feeder, along atransmission line of the feeder. The fifth conductor of the feeder iselectrically connected to the resonator. More specifically, the fifthconductor is connected to a first signal conducting portion of theresonator. Accordingly, the input current flows in the resonator, aswell as, in the feeder. The input current flows in a counterclockwisedirection in the resonator. The input current flowing in the resonatorcauses a magnetic field to be formed, so that induced current may begenerated in the resonator due to the magnetic field. The inducedcurrent flows in a clockwise direction in the resonator. For example,the induced current transfers energy to a capacitor of the resonator,and a magnetic field is formed due to the induced current. In thisexample, the input current flowing in the feeder and the resonator isindicated by a solid line of FIG. 4A, and the induced current flowing inthe resonator is indicated by a dotted line of FIG. 4A.

A direction of a magnetic field formed due to a current may bedetermined based on the right hand rule. As illustrated in FIG. 4A,within the feeder, a direction 421 of a magnetic field formed due to theinput current flowing in the feeder is identical to a direction 423 of amagnetic field formed due to the induced current flowing in theresonator. Accordingly, the strength of the total magnetic fieldincreases within the feeder.

Additionally, in a region between the feeder and the resonator, adirection 433 of a magnetic field formed due to the input currentflowing in the feeder has a phase opposite to a phase of a direction 431of a magnetic field formed due to the induced current flowing in thesource resonator, as illustrated in FIG. 4A. Accordingly, the strengthof the total magnetic field decreases in the region between the feederand the resonator.

Typically, a strength of a magnetic field decreases in the center of aresonator with the loop structure, and increases outside the resonator.However, referring to FIG. 4A, the feeder is electrically connected toboth ends of a capacitor of the resonator, and accordingly the inducedcurrent of the resonator flows in the same direction as the inputcurrent of the feeder. Since the induced current of the resonator flowsin the same direction as the input current of the feeder, the strengthof the total magnetic field increases within the feeder, and decreasesoutside the feeder. As a result, the strength of the total magneticfield increases in the center of the resonator with the loop structure,and decreases outside the resonator, due to the feeder. Thus, thestrength of the total magnetic field is equalized within the resonator.

The power transmission efficiency for transferring power from theresonator to a target resonator is in proportion to the strength of thetotal magnetic field formed in the resonator. In other words, when thestrength of the total magnetic field increases in the center of theresonator, the power transmission efficiency also increases.

Referring to FIG. 4B, the feeder 440 and the resonator 450 are expressedas equivalent circuits. An example of an input impedance Z_(in) viewedin a direction from the feeder 440 to the resonator 450 may becalculated, as indicated in Equation (4) below.

$\begin{matrix}{Z_{in} = \frac{\left( {\omega\; M} \right)^{2}}{Z}} & (4)\end{matrix}$

In Equation (4) above, M denotes a mutual inductance between the feeder440 and the resonator 450, ω denotes a resonance frequency between thefeeder 440 and the resonator 450, and Z denotes an impedance viewed in adirection from the resonator 450 to a target device.

The input impedance Z_(in) is in proportion to the mutual inductance M.Accordingly, the input impedance Z_(in) is controlled by adjusting themutual inductance M. The mutual inductance M may be adjusted based on anarea of a region between the feeder 440 and the resonator 450. The areaof the region between the feeder 440 and the resonator 450 may beadjusted based on a size of the feeder 440. Accordingly, the inputimpedance Z_(in) may be determined based on the size of the feeder 440,and thus a separate matching network may not be required to performimpedance matching with an output impedance of a PA.

In a target resonator and a feeder that are included in a wireless powerreception apparatus, a magnetic field may be distributed as illustratedin FIG. 4A. For example, the target resonator receives wireless powerfrom a source resonator through magnetic coupling. Due to the receivedwireless power, induced current is generated in the target resonator. Amagnetic field formed due to the induced current in the target resonatorcauses another induced current to be generated in the feeder. In thisexample, when the target resonator is connected to the feeder asillustrated in FIG. 4A, the induced current generated in the targetresonator flows in the same direction as the induced current generatedin the feeder. Thus, the strength of the total magnetic field increaseswithin the feeder, but decreases in a region between the feeder and thetarget resonator.

FIG. 5 illustrates an example of an electric vehicle charging systemaccording to an embodiment of the present invention.

Referring to FIG. 5, an electric vehicle charging system 500 includes asource system 510, a source resonator 520, a target resonator 530, atarget system 540, and an electric vehicle battery 550.

The electric vehicle charging system 500 has a similar structure to thewireless power transmission system of FIG. 1. The source system 510 andthe source resonator 520 in the electric vehicle charging system 500function as a source. Additionally, the target resonator 530 and thetarget system 540 in the electric vehicle charging system 500 functionas a target.

The source system 510 includes a variable SMPS, a PA, a matchingnetwork, a TX controller, and a communication unit, similarly to thesource 110 of FIG. 1. The target system 540 includes a matching network,a rectifier, a DC/DC converter, a communication unit, and an RXcontroller, similarly to the target 120 of FIG. 1.

The electric vehicle battery 550 is charged by the target system 540.

The electric vehicle charging system 500 uses a resonant frequency in aband of a few kilohertz (KHz) to tens of megahertz (MHz).

The source system 510 generates power, based on a type of chargingvehicle, a capacity of a battery, and a charging state of a battery, andsupplies the generated power to the target system 540.

The source system 510 controls the source resonator 520 and the targetresonator 530 to be aligned. For example, when the source resonator 520and the target resonator 530 are not aligned, the controller of thesource system 510 transmits a message to the target system 540, andcontrols alignment between the source resonator 520 and the targetresonator 530.

For example, when the target resonator 530 is not located in a positionenabling maximum magnetic resonance, the source resonator 520 and thetarget resonator 530 may not be aligned. When a vehicle does not stopaccurately, the source system 510 induces a position of the vehicle tobe adjusted, and controls the source resonator 520 and the targetresonator 530 to be aligned.

The source system 510 and the target system 540 transmit or receive anID of a vehicle, or exchange various messages, through communication.

The descriptions of FIGS. 1 through 4B apply to the electric vehiclecharging system 500. However, the electric vehicle charging system 500uses a resonant frequency in a band of a few KHz to tens of MHz, andtransmits power that is greater than or equal to tens of watts to chargethe electric vehicle battery 550.

FIGS. 6A to 7B illustrate applications using a wireless power receptionapparatus and a wireless power transmission apparatus according to anembodiment of the present invention.

Referring to FIGS. 6A and 6B, FIG. 6A illustrates an example of wirelesspower charging between a pad 610 and a mobile terminal 620, and FIG. 6Billustrates an example of wireless power charging between pads 630 and640 and hearing aids 650 and 660.

For example, a wireless power transmission apparatus is mounted in thepad 610, and a wireless power reception apparatus is mounted in themobile terminal 620. The pad 610 is used to charge a single mobileterminal, namely, the mobile terminal 620.

In another example, two wireless power transmission apparatuses arerespectively mounted in the pads 630 and 640. The hearing aids 650 and660 are used for a left ear and a right car, respectively. In thisexample, two wireless power reception apparatuses are respectivelymounted in the hearing aids 650 and 660.

Referring to FIGS. 7A and 7B, FIG. 7A illustrates an example of wirelesspower charging between an electronic device 710 that is inserted into ahuman body, and a mobile terminal 720. FIG. 7B illustrates an example ofwireless power charging between a hearing aid 730 and a mobile terminal740.

For example, a wireless power transmission apparatus and a wirelesspower reception apparatus are mounted in the mobile terminal 720. Inthis example, the wireless power reception apparatus is mounted in theelectronic device 710. The electronic device 710 is charged by receivingpower from the mobile terminal 720.

In another example, a wireless power transmission apparatus and awireless power reception apparatus are mounted in the mobile terminal740. In this example, the wireless power reception apparatus is mountedin the hearing aid 730. The hearing aid 730 is charged by receivingpower from the mobile terminal 740. Low-power electronic devices, suchas Bluetooth earphones, may also be charged by receiving power from themobile terminal 740.

FIG. 8 illustrates an example of a wireless power transmission apparatusand a wireless power reception apparatus according to an embodiment ofthe present invention.

For example, a wireless power transmission apparatus 810 of FIG. 8 ismounted in each of the first pad 630 and the second pad 640 of FIG. 6.In another example, the wireless power transmission apparatus 810 ismounted in the mobile terminal 720 of FIG. 7A and/or the mobile terminal740 of FIG. 7.

Additionally, a wireless power reception apparatus 820 of FIG. 8 ismounted in each of the hearing aids 650 and 660 of FIG. 6.

The wireless power transmission apparatus 810 is configured similarly tothe source 110 of FIG. 1. For example, the wireless power transmissionapparatus 810 includes a unit configured to transmit power usingmagnetic coupling.

In FIG. 8, a communication/tracking unit 811 communicates with thewireless power reception apparatus 820, and controls an impedance and aresonant frequency to maintain a wireless power transmission efficiency.For example, the communication/tracking unit 811 performs similarfunctions to the TX controller 114 and the communication unit 115 ofFIG. 1.

The wireless power reception apparatus 820 is configured similarly tothe target 120 of FIG. 1. For example, the wireless power receptionapparatus 820 includes a unit configured to wirelessly receive power andto charge a battery. As illustrated in FIG. 8, the wireless powerreception apparatus 820 includes a target resonator (or an RXresonator), a rectifier, a DC/DC converter, and a charger circuit.Additionally, the wireless power reception apparatus 820 includes acommunication/control unit 823.

The communication/control unit 823 communicates with the wireless powertransmission apparatus 810, and performs an operation to protect againstovervoltage and overcurrent.

The wireless power reception apparatus 820 includes a hearing devicecircuit 821. The hearing device circuit 821 is charged by the battery.The hearing device circuit 821 includes a microphone, anAnalog-to-Digital Converter (ADC), a processor, a Digital-to-AnalogConverter (DAC), and a receiver. For example, the hearing device circuit821 has the same configuration as a hearing aid.

FIGS. 9A and 9B illustrate a stereoscopic flexible resonator 910, and afield distribution based on a resonance mode of a resonator according toan embodiment of the present invention.

Typically, when an RX resonator and a TX resonator face each other, aresonator for wireless power transmission may have its highesttransmission efficiency. When an angle of one of the RX resonator andthe TX resonator facing each other is changed, the transmissionefficiency may be significantly reduced. Accordingly, a characteristicin a transmission direction may be limited. Additionally, considering apractical situation of a mobile device and a medical device, atransmission efficiency of a Printed Circuit Board (PCB) used as aconductor in a device may be significantly reduced, when the PCB islocated between the RX resonator and the TX resonator. Accordingly, inwireless charging of a mobile phone, a small electronic device, or amedical device, power transmission efficiency may be reduced based on alocation in which a device is placed.

A stereoscopic flexible resonator according to an embodiment of thepresent invention may maintain a high power transmission efficiency,regardless of a location of a device, and may have a mode to effectivelyform a magnetic near field suitable for a shape of a transmission andreception apparatus for wireless power transmission. Additionally, thestereoscopic flexible resonator may be used as a source resonator, or atarget resonator.

The ideal three Dimensional (3D) stereoscopic flexible resonator 910 ofFIG. 9A has a hexahedral structure, and resonators, each having arectangular shape, have predetermined intervals in x, y, and zdirections. Each of the resonators includes a capacitor and an inductorhaving a shape of a single loop or a multi-loop with an arbitrary shape,an arbitrary size, and an arbitrary thickness. Additionally, each of theresonators may have an arbitrary resonant frequency. In the presentinvention, the terms “3D resonator,” “stereoscopic resonator,” and “3Dstereoscopic resonator” may be interchangeably used with respect to eachother.

Referring to FIG. 9B, an ideal 3D stereoscopic resonator including aplurality of resonators have various resonance modes. In the graph ofFIG. 9B, a vertical axis represents an input impedance in ohms (Ω), anda horizontal axis represents a resonant frequency in MHz.

According to an embodiment of the present invention, it is possible toselect modes corresponding to a single direction, both directions, andall directions based on a scheme of setting a resonant frequency of aresonator and applying power. Accordingly, it is possible to select anappropriate mode based on a use environment and a shape of a devicerequiring wireless power transmission.

In FIG. 9B, a resonator 911 set in a first resonance mode shows anH-field distribution 921, and has a resonant frequency corresponding toa first peak point of the input impedance in the graph. A resonator 912set in a second resonance mode shows an H-field distribution 922 in bothdirections, and has a resonant frequency corresponding to a second peakpoint of the input impedance in the graph. In addition, a resonator 913set in a third resonance mode shows an H-field distribution 923 in alldirections, and has a resonant frequency corresponding to a third peakpoint of the input impedance in the graph.

A resonance mode of a 3D stereoscopic resonator is not limited to theabove three resonance modes, and a plurality of resonance modes may beprovided based on a scheme of setting a resonant frequency and applyingpower.

FIGS. 10A and 10B illustrate examples of a structure of a stereoscopicflexible resonator according to an embodiment of the present invention.

A stereoscopic flexible resonator includes a plurality of cells. In ascheme of inducing a current to flow in the cells, the cells areconnected in a direct configuration or a cross configuration, or acapacitor may be inserted.

For example, in a stereoscopic flexible resonator 1010, a cell and aresonator 1011, each having a rectangular shape, are connected in ahexahedral structure through a connection unit 1012. The cell includes aconnection unit and an inductor having a shape of a single loop or amulti-loop, instead of including a capacitor. A resonator includes aninductor and a capacitor. The cell is connected to the resonator throughthe connection unit, to form a single 3D stereoscopic resonator.Additionally, a loop shape of each of the cell and the resonator is notlimited to a rectangle, and includes all shapes used to form a loop.

In another example, in FIG. 10B, a stereoscopic flexible resonator 1020,a cell and a resonator 1021, each having a triangular shape, areconnected in a tetrahedral structure through a connection unit 1022. Aloop shape of each of the cell and the resonator is not limited to atriangle, and includes all shapes used to form a loop.

In still another example, in a stereoscopic flexible resonator, a celland a resonator, each having an arbitrary shape, are connected in apolyhedral structure through a connection unit.

FIGS. 11A to 11C illustrate examples of a connection unit of astereoscopic flexible resonator according to an embodiment of thepresent invention. The stereoscopic flexible resonator includes a singlecell and a single resonator.

In resonators 1111 connected through a connection unit 1112 having adirect configuration as shown in FIG. 11A, currents flow in the samedirection. For example, when a current flows in a left loop in aclockwise direction, a current also flows in a right loop in theclockwise direction.

In resonators 1121 connected through a connection unit 1122 having across configuration as shown in FIG. 11B, currents flow in oppositedirections. For example, when a current flows in a left loop in aclockwise direction, a current flows in a right loop in acounterclockwise direction.

Resonators 1131 are connected through a connection unit 1132 having ashape of a capacitor as shown in FIG. 11C. Loops of the resonators arecoupled by capacitors, and a direction and magnitude of a current ischanged based on a capacitance of each of the capacitors.

FIGS. 12A and 12B illustrate examples of a resonance mode based on aselection of a connection unit of a stereoscopic flexible resonatoraccording to an embodiment of the present invention.

A connection unit having a direct configuration or a cross configurationinduces a current to flow in the same direction as or an oppositedirection to a direction of a current flowing in a neighboring cell.Accordingly, by selecting a type of connection units as shown in FIGS.12A and 12B, a field of a 3D stereoscopic resonator is selected.Similarly, when a capacitor is inserted into a cell and the cell is usedas a resonator having an arbitrary resonant frequency, a direction andan intensity of a current is adjusted based on a scheme of selecting aresonant frequency. In other words, by changing a capacitance of thecapacitor, a mode of a magnetic near field is changed suitably for ashape of a device. A resonance direction of a resonance mode isdetermined by a direction of a current flowing in each of a cell and aresonator, based on a right-handed screw rule.

In a stereoscopic flexible resonator 1210 of FIG. 12A, cells andresonators 1211 are connected in a hexahedral structure via a connectionunit 1212 having a direction configuration and a connection unit 1213having a cross configuration. The stereoscopic flexible resonator 1210is set in the same resonance mode as the resonance mode of thestereoscopic resonator 911 of FIG. 9. Accordingly, when the right-handedscrew rule is applied to directions of currents flowing in cells andresonators, a resonance direction corresponds to a single direction.

In a stereoscopic flexible resonator 1220 of FIG. 12B, cells andresonators 1221 is connected in a hexahedral structure via connectionunits 1222, each having a direction configuration. The stereoscopicflexible resonator 1220 is set in the same resonance mode as theresonance mode the stereoscopic resonator 913 of FIG. 9. When theright-handed screw rule is applied to directions of currents flowing incells and resonators, a resonance direction corresponds to alldirections.

Although a few embodiments have been shown and described, the presentinvention is not limited to the described embodiments. Instead, it willbe apparent to those skilled in the art that various modifications andvariations can be made to these embodiments without departing from thescope and spirit of the invention.

Thus, the scope of the present disclosure is not limited to theabove-described embodiments, but is defined by the appended claims andtheir equivalents.

The invention claimed is:
 1. A resonator for wireless powertransmission, the resonator comprising: a plurality of cells throughwhich current of the wireless power transmission flows comprising acapacitor; and a connection unit configured to connect the plurality ofcells to form a three dimension (3D) structure, wherein the connectionunit is configured to connect the plurality of cells with a directconfiguration or a cross configuration according to a selected resonancemode.
 2. The resonator of claim 1, wherein a resonance mode is changedbased on a change in a value of the capacitor.
 3. The resonator of claim1, wherein the connection unit is further configured to connect theplurality of cells in a hexahedron structure.
 4. The resonator of claim1, wherein the connection unit is further configured to connect theplurality of cells in a tetrahedral structure.
 5. The resonator of claim1, wherein the connection unit is further configured to connect theplurality of cells in a polyhedral structure.
 6. The resonator of claim1, wherein the connection unit is further configured to connect theplurality of cells so that the selected resonance mode corresponds to asingle direction.
 7. The resonator of claim 1, wherein the connectionunit is further configured to connect the plurality of cells so that theselected resonance mode corresponds to two directions.
 8. The resonatorof claim 1, wherein the connection unit is further configured to connectthe plurality of cells so that the selected resonance mode correspondsto all directions.
 9. The resonator of claim 1, wherein the plurality ofcells comprises an inductor.